Process of treating waste sulfite liquor and compound obtained.



UNITED s'rArn s ATENr OFFICE.

JACOB S. ROBESCN, OF CAMDEN, NEW JERSEY. PROCESS OF TREATING WASTE SULFITE'LIQUOR AND COMPOUND. OBTAINED.

T0 at whom it may concern.-

Be it known that I, JAooB S. ROBESON, a citizen of the United States, and a resident of Camden, Camden county, New Jersey, have invented an Improved Process of Treating Waste Sulfite Liquor and Compound Obtained Therefrom, of which the following is a specification.

My invention relates to the utilization of the waste liquor resulting-from the manufacture of cellulose or fibers from various woods and woody materials, and particularly spruce-wood, (Picea sp.,) by boiling under pressure with a solution containing sulfurous acid and a base or bases, such as lime or magnesia, under what is known as the sulfite process.

My invention consists of a special method of treating said waste liquor (hereinafter termed sulfite liquor) whereby I am enabled to increase the density of the mass,

which ma be brought to a state of dryness, and there y secure a composition of matter (which also constitutes part of my invention) having valuable properties and novel and unique characteristics whichrender it highly suitable for various purposes, notably as a binding a ent for the material employed in the manu acture of cores for casting, as well as for other finely-divided inorganic material of varied character to form any desired shapes, forms, or masses.

The exact nature of the reaction in the treatment of wood by the su lfite process is not known, and it probably differs materially with each particular wood treated. In general it is known that the sulfite solution combines with and dissolves high-molecular complexes related to and associated with the cellulose without much changing their chemical nature or breaking down the molecules to any great extent, and it also dissolves an indefinite number of other bodies like tannins, gums, acids, sugars, &c. The principalbody contained in these sulfite li uors has been" called by many chemists, Without necessarily implying any very defi nite conception of its chemical composition, a li nosulfonate .of the base which occurre in the original sulfite solution-ligno sulfonate of lime, for example. This word lignosulfonate must be taken purely as a group term, since the waste liquors derived om different woods are certainly very different, as different as the cellulose derived from the. same woods, as I have found, for

Specification of Letters'Patent; A ucaam filed March 12, 1906. Serial No. 306,705.

, Patented Oct. 16, 1906.

example, in the case of the liquor derived from spruce-wood, which displays many characteristics different from those of the other known liquors. The substances in the liquor, although sufficiently stable under the conditions of formation, seem to be uite sensitive when the liquor is heated elsew iere. under improper conditions' Many efforts have been made 'to utilize this solution, since the highly colloid and adhesive nature of the dissolved solids render it of evident value if it could be concentratedto a useful degree. Simple evaporation in open pans has been repeatedly tried; but since this inevitably results in more or less decomposition, attended with the breaking down and deposition of insoluble forms of the organic bodies and the liberation of noxious gases,

attention has lately been directed to various chemical treatments before or after evaporation. These methods, while perhaps valuable in certain cases, do not give the result soughta concentrated solution of the substantially unchan ed or anic bodies from the wood in the su fite so vent still preservin their highly colloid nature and great ad esiveness. I c

When evaporation is carried out in an open pan, the liquid, even when neutralized to begin with, rapidly becomes acid and evolves unpleasant gaseous products and also deposits insoluble matter, becoming turbid. Neutralization during evaporation does not seem to revent this reaction. The resulting thic 'ened solution does not possess the valuable properties whicli could have been expected from the character of the original sulfite liquor, and it has been found tohave no commercial value.

The varying density of the liquor (a constant factor) renders its evaporation in an open pan impracticable, since not only is' there the necessity for constant and careful regulation of the heatemployed, but each batch of 1i uor must be differently treated, the "initial eat applied invarying degree, and the resulting vapors, due to decomposition of the liquid as soon as an initial neutralization, if performed, has been destroyed, are so obnoxious as to render such treatment amenable to the laws regarding nuisances. Furthermore, in this treatment there is the necessity of regulating and quickly checking the heat when the concentrated liquor approaches the point of desired density, for it is well known that decomposition accelerates the impossibility of making a product such as I desire, render such atmospheric evapo-' ration practically valueless. The cause of this decompositionof the liquor in the .ordi-v nary method of evaporation I am unable to state, merely noting the fact. It may perhaps be due to the high temperature incident to boiling under ordinary atmospheric pressure, a temperature, so to speak, exceedmg the critical temperature of the sulfite combinations heated alone and without the presence of the excess. of sulfur compounds which they had in the digester, or it may be due to oxidationphenomena, or'very likely to both combined. At all events I have discovered that if the sulfite liquor be nearly or quite neutralized by any convenient base, such as soda or lime, and then evaporated quickly at a temperature not exceeding 100 centigrade, under exclusion of air, it may be brought down to any desired degree of concentration, or even to dryness,without.de composition and without loss ofits colloid nature, adhesive character, or other properties. While there are certain other sulfite liquors which are alleged to stand an evaporation at temperatures slightly above 100 centigrade, this is not possible with spruce lliqluor showing one of the radical differencesave found to exist. Evaporation may be effected by a wide variety of machines and methods so-long as thetem era'tu're'is carefully controlled and the 02d izing influence of the air'excluded'. The li'qu'or' may, for instance, be condensed by a streamof as circulating in a closed circuit a enter, through or over the solution, t 'rou h a condenser, conveniently water-cooled, I on, by bubblin the as through the solution or over' thinvices, or in any other convenient manner.

' Any ind-ifierent gasmay be employed-nitrogen, carbon dioxid, producer-gas, or even air, the last-named in the limited amount contained in an ordinary closed-circuit appara-tus not possessing enough oxygen to harmfully affect more than the first portions of solution treated, which may ofcourse be run to'waste, if necessary; but at present I prefer vacuum evaporation, either in an ordrnary vacuum-pan or in the transit-film evaporators.

I regard my invention as covering, broadly,

any method of'conce'ntrating the solution, employing a relatively low tem erature, below the normal boiling-point 0 water,; and operating under exclusion of oxidation.

When overheated locally or throughout its mass, sulfite liquor begins to decompose,

and when this reactiononce' sets in it ap'-- ack through the heater, and so ms ormed by rotating' depears to be self-accelerating to an indefinite extent. For this reason in evaporation even in vacuum-pans it is necessary not only to guard against overheating of the Whole mass of li uid, but such local overheating as might resu t from the use of high-pressure steam or improperly-designed heating elements.

In carr, in out my invention I take the waste sul te iquor as it comes from the di gester and render it neutral, or substantiall so, by the addition of a suitable alkali-or a kaline earth, such as milk of lime or caustic soda, as may be mostconvenient or desirable. The quantity of the neutralizing agent used will vary,'depending u on the quantity of free acid in the sulfite iquor, and the amount to be added to render such. liquor neutral, or nearly so, may be determined by the usual tests. After the sulfite liquor has been neutralized (and I may-state that it is not necessary to make it absolutely neutral,

as a liquor ver slightly acid will produce e ually desirab e results) I concentrate the su fite liquor after the manner above noted. The sulfite liquor is treated until it has been concentrated to a consistency of about 30 Baum, such liquor having been received in the concentrating apparatus in a very thin state.

In neutralizing, care must be taken not to overstep the neutral point by an addition of an excess of alkali, smce in the presence of alkalies the complex compounds formed by sulfites with organic matters tend to break up.

In the operation of the method of evaporacondensed va ors are innocuous and may be utilized shoud occasion require or run to waste without danger of causing any harmful results.

When employed in the. manufacture of sand cores or the making of any shapes from finely-divided inorganic matter, the concentrated material is employed n the for'mof a liquid, preferably at a density from 18 to 20 Baum, and it will bev understood that the density of the'material in the liqu d form will do end upon the use to which it is to be put. or certain connnerclal' purposes, however, I may evaporate or concentrate the waste li uor to dryness, in which state it may be in a aky condition and may be reduced to owder by any suitable means. When use in connection with the manufacture of cores, the re u-ired amount of this powder may be adde to a quantity of.water sufii cient to bring the mixture to the required density to form the binding a cut.

In connection with my wor of utilizing waste sulfite liquors I have had much occasion to handle that resulting from the treatment of spruce-wood (Pic'ea 8p.) by the usual bisulfite methods of recover ng cellulose. This liquor appears to contain Substances differing quite materially from those found in other sulfite liquors, and for chemical tigated the natural celluloses it appears that the various woods an there are Substantial differences in the cellulose contamin g complexes or molecules which form the ultimate basis of' each individual wood or fiber, these differences corresponding to the well-known hysical differences of fibers of commerce. The cellulose portion of the molecule is probably, broadly considered, much 'the same in each woody fiber, or at least that portion which is split off by the sulfite treatment and called cellulose; but the portion which goes into solution in the bisulfite is quite different in molecular magnitude and other respects This difference in magnitude of the portion dissolving and the portion undissolved causes the difference in yield with various woods under the same process, and the chemical difference is the reason why a method of sulfite cooking (concentration of liquor, heat, &c.) adapted to one wood is seldom applicable to another without modification. The conclusion that physical differences in the wood are largely functions of chemical differences in the fiber is corroborated by experience with various sulfite liquors wherein the complex, usually called lignon'e, which is united with the sulfite radical, appears to be quite different in the liquors from different woods. .The 1i nor from spruce yields products by my met od which appear to have exceptionally advantageous properties for many commercial uses. My process appears particularly adapted to this liquor, and my products therefrom are specially advantageous.

Concentrated sulfite liquors made by my process differentiate from those of the prior artby the fact that they ive no precipitate with strong solutions of'gelatin or glue.

The resultantdried mass from the concentrated and undecomposed liquor is in a flaky condition, and a fluid solution of the same or the concentrated liquor formed-by my method may be distinguished from the liquor concentrated by prior methods or processes by its relative clearness or translucency and by its complete solubility in water, the products previously known having a markedly muddy or turbid appearance and containing particles of insoluble material resulting from decomposition. By the addition of a quantity of water equaling that removed by evaporation the original liquor may be reproduced,

- showing that its constituents have undergone no injurious change.

I have discovered that this neutral and concentrated composition of matter produced by my improved process or method is very suitable for mixing with sand to form cores, the particular advantage and property being that it will combine with all known sands, causing the same to pack and adhere and retain their size and shape when dry, a condition unattained by the use of any of the usual or well-known so-called core compounds or core-sand-binding materials or adhesives in use at the present time. In addition, it may be employed as a binder for all kinds of inorganic granular material in making plastic masses.

When employed with material that is ground or milled preparatory to being molded into shape, the concentrated material to form the binding agent may be added in the dry stateand ground or milled or otherwise mixed with the other material, and the mixture thus prepared requires simply the addition of water to bring it to the desired molding or shapin condition.

claim- 1. The method oftreating waste sulfite liquor, which consists in rendering such liq uor substantially neutral, and then concentrating it in vac a0.

2. The method of treating waste sulfite liquor, which consists in rendering such liq uor substantially neutral by the addition of milk of lime, and then evaporating said mixture in vacuo.

3. The method of treating waste sulfite liquor, which consists in rendering such liquor substantiallyneutral, and then evaporating it in vacuo to a consistency of about Y 30 Bauin.

41 The method of treating waste sulfite liquor, which consists in rendering such liquor substantially neutral by the addition of milk of lime, and then evaporating said mixture in vacuo to a consistency of about 30 Baum.

5. The method of treating waste sulfite liquor from the digestion of spruce-wood, which consists in rendering such liquor substantially neutral, and then concentrating it in vacuo.

6. The method of treating waste liquor from the digestion of spruce-wood, which consists in rendering such liquor substantially neutral by the addition of milk of lime, and then evaporating it in vacuo.

7. The method of treating waste sulfite liquor from the digestion of spruce-wood,

which consists in rendering such liquor substantially. neutral by the addition of milk of lime, and then evaporating said mixture in vacuo to a consistency of about 30 Baum.

9. A composition of matter consisting ofa concentrated, substantially neutral and clear solution of the essential substances of waste sulfite liquor chemically unchanged.

10. \{X composition of matter consisting of a substantially neutral and concentrated mass of waste sulfite liquor, relatively clear or translucent on initial concentration, and

having strong adhesive properties.

11. A composition of matter consisting of a substantially neutral and concentrated mass ofwaste sulfite liquor reduced to a consistency of about 80 Baum, relatively clear or translucent on initial concentration, and having strong adhesive properties.

12. A composition of matter consisting of a substantially neutral, concentrated and undeconiposed mass of waste sulfite liquor, relatively clear or translucent on initial concentration, and having strong adhesive properties.

13. A composition of matter consisting of a substantially neutral, concentrated and undecomposed mass of. waste sulfite liquor reduced to a consistency of about Baum. relatively clear or translucent on initial concentration, and having strong adhesive propertles.

14. An adhesive product consisting of the concentrated constituents of waste sulfite liquor, characterized by having had a neu- '.tralizing agent added lhereto, by being entirely soluble, and by being'relatively clear or translucent on initial concentration.

1.5. An adhesive product consisting of the constituents of waste sulfite liquor in a concentrated state, characterized by having had a neutralizing agent added thereto, the bulk of the-water extracted therefrom, by being entirely soluble, and by being relatively clear or translucent on initial concentration.

16. An adhesive product consisting of the concentrated constituents of a neutralized mass of waste sulfite liquor, characterized by having had a neutralizin a ent added thereto, by being entirely so ubie, and by being relatively clear or translucent on initial c011- centration.

17. An adhesive comprising a concentrated waste sulfite liquor, clearly soluble in water, and in strong solutions not precipitating glue solutions.

18. An adhesive comprising a concentrated Waste sulfite liquor from the digestion of spruce-wood, clearly soluble in water, and in strong solutions not precipitating glue 'solutions.

19. A composition of matter consistin of a concentrated substantially neutral c ear solution of the essential substances of Waste sulfite liquor from the digestion of spruce- Wood chemically unchanged.

20. A composition of matter consisting of a substantially neutral and concentrated mass of waste sulfite liquor from the digestion of spruce-wood, relatively clear or translucent on initial concentration, andhaving strong adhesive properties.

21. An adhesive product consisting of the concentrated constituents of Waste sulfite liquor from the digestion of spruce-Wood, characterized by having had a neutralizing a ent added thereto. by being entirely solub e, and by being relatively clear or translucent on initial concentration.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

, JACOB s. ROBESON. 

